<p>Sakky, it is difficult to compare graduate rates from one university to another. Graduation rates have a lot to do with a university’s curricular philosophy and mission. For example, Michigan has many programs that require more than 4 years to complete.
As such, one can argue that Michigan should do more to facilitate quicker graduation. </p>
<p>However, two things are certain, and on these points, you are wrong; </p>
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<li><p>Michigan students do not have to put up with classes that enroll 1,000. In fact, the largest lecture hall at Michigan seats 600 students, and there are only a handful of lecture halls at the university of Michigan that can accommodate more than 300 students. Obviously, as a larger university, Michigan is going to have larger classes than Harvard, on average. But the difference is not as glaring as one would think. Even Harvard has classes that enroll over 300 students. </p></li>
<li><p>Michigan students are seldom locked out of classes due to over enrollment and in my 20 years of following Michigan closely, I have never heard of a single case where a student had to delay graduation plans as a result of administrative inefficiency (be it over enrolling or whatever). </p></li>
</ol>
<p>Could Michigan alter its curriculum to facilitate high four-year graduation rates? Sure, but at the expense of providing undergraduates enrolled in certain programs with the substance that the department feels is required. Students wishing to double major in LSA and the School of Music or LSA and the College of Architecture or Engineering and LSA or LSA and Public Affairs/Policy, to mention only very few popular double majors open to Michigan stuents, will usually require more than 4 years to complete all required courses for graduation. </p>
<p>There are obviously other factors that go into determining graduation rates. Financial need/obligation is the most obvious one. Let us be honest here, there are many students at Michigan who are paying $12,000 in tuition (or less thanks to merit scholarship) and probably just as many students at Harvard who are paying $40,000 in tuition and come from well-off but not wealthy families. The former are not motivated to complete their studies in 4 years, particularly if their program is demanding, or if they plan on applying to graduate programs that require very high GPAs and can afford to pace themselves by taking a more manageable courseload to maintain a high GPA or if they are having too good a time! 
The latter, on the other hand, are under a great deal of pressure to graduate as quickly as possible. </p>
<p>At any rate, I am fairly certain that the OP did not intend to imply that Michigan (or Cal) should be ranked #1 and/or compared to Harvard. Everybody knows that Harvard (along with MIT, Princeton, Stanford and Yale), is the best. Rather, I think the OP was trying to understand why Cal and Michigan are rated much better at the graduate level than they are at the undergraduate level. The reason is simple; ranking methodologies are one-dimentional, often commercial in nature and almost always dependent on faulty, irrelevant and inconsistent data. If properly and honestly conducted, Cal and Michigan’s undergraduate and graduate programs should be rated equally.</p>